JEE Mains · Maths · STD 11 - Trigonometrical equations
With the usual notation, in \(\Delta ABC\), if \(\angle A + \angle B = {120^o}\), \(a = \sqrt 3 - 1\), then the ratio \(\angle A : \angle B\), is
- A \(7 : 1\)
- B \(5 : 3\)
- C \(9 : 7\)
- D \(3 : 1\)
Answer & Solution
Correct Answer
(A) \(7 : 1\)
Step-by-step Solution
Detailed explanation
\(a=\sqrt{3}+1\) \(b=\sqrt{3}-1\) \(\frac{\sin A}{\sin B}=\frac{\sqrt{3}+1}{\sqrt{3}-1}=\frac{3+1+2 \sqrt{3}}{2}=2+\sqrt{3}\) \(\frac{\sin A}{\sin (120-A)}=\sqrt{3}+2\) \(\frac{\sin A}{\sin 12 \cos A-\cos 12 \sin A}=\sqrt{3}+2\)…
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